package xyz.bernkastel.goods_in_great_demand.filter;

import com.alibaba.fastjson.JSON;

import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;
import xyz.bernkastel.goods_in_great_demand.common.BaseContext;
import xyz.bernkastel.goods_in_great_demand.common.R;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否完成登录的拦截器
 */
@WebFilter(filterName = "LoginCheckFilter", urlPatterns = "/*")//设置拦截器，拦截所有请求
@Slf4j
public class LoginCheckFilter implements Filter {
    //路径匹配器，支持通配符匹配
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;//转换类型
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //log.info("请求的url：{}",request.getRequestURI());


        //1、获取本次请求的URI
        String requestURI = request.getRequestURI();
        //定义不需要处理的请求路径
        String[] noProcessingURIs = new String[]{
                "/employee/login",
                "/employee/logout",
                "/employee/checkcode",
                "/common/**",
                "/backend/**",//放行静态资源
                "/front/**",
                "/user/sendMsg",
                "/user/login",
                "/pay/**"
        };
        //2、判断本次请求是否需要处理
        Boolean check = Check(noProcessingURIs, requestURI);

        //3、如果不需要处理，则直接放行
        if (check) {
            //log.info("不需要处理的url：{}",request.getRequestURI());
            filterChain.doFilter(request, response);//符合条件，放行请求
            return;
        }

        //4.1、判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("已经登陆，用户id：{}", request.getSession().getAttribute("employee"));

            Long empId = (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);


            filterChain.doFilter(request, response);//符合条件，放行请求
            return;
        }
        //4.2、判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("user") != null) {
            log.info("已经登陆，用户id：{}", request.getSession().getAttribute("user"));

            Long userId = (Long) request.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);


            filterChain.doFilter(request, response);//符合条件，放行请求
            return;
        }

        //5、如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
        //log.info("用户未登录");
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));//对应/backend/request.js 47行的响应式拦截器

    }

    /**
     * 路径匹配函数，用来判断请求路径是否需要放行
     *
     * @param noProcessingURIs 可以放行的url集合
     * @param requestURI       本次请求的url
     * @return 返回匹配结果
     */
    public Boolean Check(String[] noProcessingURIs, String requestURI) {
        for (String url : noProcessingURIs) {
            boolean match = PATH_MATCHER.match(url, requestURI);//匹配url是否与库中相同
            if (match) {
                return true;
            }
        }
        return false;
    }
}
